How to Encounter

Japanese River Otter remains extremely elusive to encounter without luck, as the 4-star Wooden Water House added upon her release is her only non-limited rateup.
Out of her limited 3-star rateups, the Sasakazari is the most effective, due to it only having one other rateup.

Unique Behavior

かくれんぼ (Hide-and-Seek) - Hides inside the doorway of the Wooden Water House on the right side, with only her tail visible; after a while, she bobs her head out from the side and smiles.